A Tough and Self-Powered Hydrogel for Artificial Skin

Abstract

Hydrogels, because of their water-rich nature and soft mechanical characteristics that resemble those of skin tissues, are promising materials for artificial skin. Existing piezoresistive hydrogels combine unique tissue-like and sensory properties, but these materials are often plagued by problems such as poor mechanical properties and the requirement of an external power supply or batteries. Here, a tough and self-powered hydrogel based on a tough polyacrylonitrile hydrogel incorporating ferroelectric poly(vinylidene fluoride) (PAN-PVDF) is reported. The dipolar interactions between the PVDF and PAN chains cause an increase in the best electroactive β-phase PVDF percentage in the composites from 0 to 91.3%; thus, a maximum piezoelectric coefficient d 33 , 30 pC N −1 , was achieved for the hydrogels. Skin-like Young's modulus values (1.33− 4.24 MPa), stretchability (90−175%), and high toughness (1.23 MJ/m 2 ) were achieved simultaneously for the hydrogels. This tough gel is capable of generating an electrical signal output (≈30 mV and ≈2.8 μA) with a rapid response (≈31 ms) due to the stress-induced poling effect. Moreover, the gel can also precisely detect physiological signals (e.g., gesture, pulse, and words). This study provides a simple and efficient method for artificial skin with high toughness, self-power generation capability, fast response, low cost, and tissue-like properties.

RETRACTED: Amelioration of imiquimod-induced psoriasis-like dermatitis in mice by DSW therapy inspired hydrogel

“…For psoriasis, hydrogel must be durable and stress resistant in order to withstand the normal stress encountered during their application and handling which contributes to long-time drug delivery [ 14 ]. Appropriate toughness and stiffness mean that this kind of biomaterial can fit body undulation perfectly [ 15 ]. The moisturizing of the affected skin areas is beneficial for psoriasis treatment.…”

Silk‐Inspired In Situ Hydrogel with Anti‐Tumor Immunity Enhanced Photodynamic Therapy for Melanoma and Infected Wound Healing

“…As shown in Figure 2e and Figure S5, Supporting Information, under irradiation of UV light (365 nm, 50 mW cm −2 ), the storage modulus of SFMA‐Ce6 (10% w/v) solution increased rapidly within 3 min irradiation and gel point was reached at 116 s. Figure 2g shows that the compressive strength of hydrogels (10% w/v) ranged from 326 to 553 kPa, which was close to human skin (500–1950 kPa). [ 42 ] The compressive strength of SFMA‐Ce6 hydrogel was found slightly lower than that of SFMA hydrogel, due to photo‐crosslinking of methacryloyl moieties close by Ce6 moieties on SF may be hindered, which decreases crosslinking density of SFMA‐Ce6 hydrogel. These results demonstrate the efficient light‐triggered gelation of SFMA‐Ce6 as an in situ formed wound dressing.…”

Effect of contact geometry on the friction of acrylamide hydrogels with different surface structures

“…Hydrogels are soft materials consisting of a threedimensional, cross-linked polymer network containing a large amount of water. The high water content (> 90 wt%) in combination with good lubricating properties of hydrogels makes them good materials to construct polymeric analogues of articular cartilage [1][2][3] or other tissues subjected to rubbing, including the trachea [4], skin [5,6], and blood vessels [7]. In order to develop hydrogels that would closely mimic natural lubrication systems and be used for medical applications, it is of great importance to understand their lubrication mechanisms.…”